high latency on 82573L

From: Tony Jones
Date: Wed Sep 01 2010 - 23:39:13 EST


Hi.

Since commit 6f461f6c7c (e1000e: enable/disable ASPM L0s and L1 and ERT
according to hardware errata) I'm seeing high latencies on my Thinkpad T60p.

02:00.0 Ethernet controller: Intel Corporation 82573L Gigabit Ethernet Controller
Subsystem: Lenovo ThinkPad T60
Flags: bus master, fast devsel, latency 0, IRQ 30
Memory at ee000000 (32-bit, non-prefetchable) [size=128K]
I/O ports at 3000 [size=32]
Capabilities: [c8] Power Management version 2
Capabilities: [d0] MSI: Enable+ Count=1/1 Maskable- 64bit+
Capabilities: [e0] Express Endpoint, MSI 00
Capabilities: [100] Advanced Error Reporting
Capabilities: [140] Device Serial Number 00-1a-6b-ff-ff-6c-7e-a4
Kernel driver in use: e1000e

# uname -r
2.6.36-rc3-0-default
# ping -c 20 192.168.1.1
PING 192.168.1.1 (192.168.1.1) 56(84) bytes of data.
64 bytes from 192.168.1.1: icmp_seq=1 ttl=64 time=1.06 ms
64 bytes from 192.168.1.1: icmp_seq=2 ttl=64 time=1007 ms
64 bytes from 192.168.1.1: icmp_seq=3 ttl=64 time=698 ms
64 bytes from 192.168.1.1: icmp_seq=4 ttl=64 time=198 ms
64 bytes from 192.168.1.1: icmp_seq=5 ttl=64 time=697 ms
64 bytes from 192.168.1.1: icmp_seq=6 ttl=64 time=1007 ms
64 bytes from 192.168.1.1: icmp_seq=7 ttl=64 time=690 ms
64 bytes from 192.168.1.1: icmp_seq=8 ttl=64 time=1007 ms
64 bytes from 192.168.1.1: icmp_seq=9 ttl=64 time=682 ms
64 bytes from 192.168.1.1: icmp_seq=10 ttl=64 time=1008 ms
64 bytes from 192.168.1.1: icmp_seq=11 ttl=64 time=1.03 ms
64 bytes from 192.168.1.1: icmp_seq=12 ttl=64 time=1007 ms
64 bytes from 192.168.1.1: icmp_seq=13 ttl=64 time=0.874 ms
64 bytes from 192.168.1.1: icmp_seq=14 ttl=64 time=1009 ms
64 bytes from 192.168.1.1: icmp_seq=15 ttl=64 time=1.72 ms
64 bytes from 192.168.1.1: icmp_seq=16 ttl=64 time=1006 ms
64 bytes from 192.168.1.1: icmp_seq=17 ttl=64 time=650 ms
64 bytes from 192.168.1.1: icmp_seq=18 ttl=64 time=1008 ms
64 bytes from 192.168.1.1: icmp_seq=19 ttl=64 time=642 ms
64 bytes from 192.168.1.1: icmp_seq=20 ttl=64 time=1643 ms

--- 192.168.1.1 ping statistics ---
20 packets transmitted, 20 received, 0% packet loss, time 19063ms
rtt min/avg/max/mdev = 0.874/698.661/1643.392/439.376 ms, pipe 2

This is 2.6.36-rc3 yet commit 19833b5dff (e1000e: disable ASPM L1 on 82573)
isn't having any effect for me.

For our OpenSUSE 11.3 kernels (2.6.34 based), reverting just 6f461f6c7c
solves the issue. For .36-rc3 reverting 6f461f6c7c plus of course 19833b5dff
does the trick.

I'm happy to perform any testing to help narrow this down. LMK.

Tony
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